The skin is the largest organ of humans. Its many functions (for example for regulation of heat and as a sense organ) include the barrier function, which prevents the skin (and therefore in the end the entire organism) from drying out, certainly the most important. At the same time, the skin acts as a protective device against penetration and uptake of substances from the outside. This barrier function is effected through the epidermis, which as the outermost layer forms the actual protective covering against the environment. With about one tenth of the total thickness, at the same time it is the thinnest layer of the skin.
The task of cosmetic skin care is to strengthen or re-establish the natural function of the skin as a barrier against environmental influences (for example dirt, chemicals, microorganisms) and against the loss of endogenous substances (for example water, natural fats, electrolytes).
The aim of skin care is furthermore to compensate for the loss of fats by the skin caused by daily washing. This is important precisely if the natural capacity for regeneration is not sufficient.
A central task of skin care is moisturizing of the skin. The moisture content of the skin has an important influence on its appearance and its state of health: the higher the water loss, the rougher and more friable the skin becomes. Its elasticity and plasticity decrease, and its intactness is no longer guaranteed. To moisturize the skin, moisturizing substances (moisturizers) which assist the water-binding capacity of the horny layer are added to cosmetic and dermatological formulations. Conventional skin moisturizers, which are employed in almost all cosmetic and dermatological formulations, include the polyols, such as glycerol and sorbitol. In addition, other compounds are also employed, such as ethoxylated polyols and hydrolyzed proteins. Components of the natural moisturizing factor of the skin (NMF), for example urea and certain amino acids, are moreover used.
A great disadvantage of the prior art is the adverse sensory properties of cosmetic or dermatological formulations which comprise polyol-containing moisturizing agents. As a rule, these feel tacky and greasy on the skin and make the corresponding products unattractive to the consumer. To suppress these negative properties, expensive silicone oils and lipids, which increase the preparation costs of the cosmetic/dermatological compositions, must be added the formulations.